the reason why the number four is still be written as IIII instead of IV in some roman clocks

The use of "IIII" instead of "IV" for the number four on some Roman clocks and sundials is based on historical and practical reasons, mainly related to design and aesthetics:

1. Aesthetic Balance: In clock faces and sundials, each numeral is often designed to occupy a consistent amount of space. With "IV," the gap between the "V" and the "I" would look empty compared to other numerals that have uniform horizontal bars (like "I," "II," "III," "V," "VI," etc.). Using "IIII" provides a more visually balanced appearance, with all numerals having similar horizontal line lengths.

2. Consistency: The "IIII" notation maintains a uniform style across all numerals, making the clock face look more harmonious. In some cases, the design of the clock might not allow for the subtraction principle (used in "IV") to be clearly or aesthetically represented due to font size or clock face design.

3. Historical Tradition: This practice has been followed for centuries, and it's become a traditional aspect of certain types of timekeeping devices. Over time, this usage has persisted, even though it doesn't strictly adhere to the subtractive principle of Roman numerals.

4. Readability: In some instances, "IIII" might be easier to read at a glance compared to "IV," especially from a distance or in low light, due to its uniformity and simplicity.

While "IIII" isn't the standard representation of the number four in Roman numerals, its use in clocks and sundials is widely accepted and understood in these contexts. It's a unique exception that showcases the blend of tradition, aesthetics, and practicality in timekeeping design.